1. Field of the Invention
The present invention relates to a disc device configured to drive optical discs (such as CD-R/RW, DVD-R/-RW/RAM/+R/+RW) that serve as record media to record mass information in information instruments such as various computer systems.
2. Description of the Related Art
In general, a disc device contained in a personal computer or the like is usually provided with a disc tray to load a disc therein and configured such that the disc tray moves forward and backward. The disc loaded in the disc tray is driven within a body of the disc device to record and reproduce information.
On the other hand, a disc device of the slot-in type is widely employed as the disc-trayless type. This tendency is suitable for thinning and downsizing the personal computer. The disc device of the slot-in type does not employ any disc tray to carry the disc in (load)/out of (unload) the device body. Therefore, after an operator inserts most of the disc into the slot, a loading mechanism in the device body is actuated such that the disc is automatically carried in.
FIGS. 51 and 52 show an arrangement and operation mode of a loading mechanism in a conventional disc device of the slot-in type. In the shown arrangement, after an operator inserts a disc D, the disc D reaches the position shown in FIG. 51. During this process, the disc is restricted for the elevation and lateral position from a tip pin 100a of a first swinging member 100 and a left and a right guide member 101, 102 and, after some midpoint, a tip pin 103a of a second swinging member 103.
At this time, the first swinging member 100 rotates in the direction of the arrow 100A as the disc D pushes the tip pin 100a. In addition, the second swinging member 103 also rotates in the direction of the arrow 103A as the disc D pushes the tip pin 103a. As pushed by the end of the second swinging member 103, a switch lever 104 rotates in the direction of the arrow 104A and actuates a detector switch 105.
When the detector switch 105 is actuated, a drive means 106 starts to operate and a first slid member 107 begins to move in the direction of the arrow 107A. The first slide member 107 and a second slide member 108 have tips linked via a slide link member 109. The slide link member 109 is swingably pivoted about a pin 110. Accordingly, in synchronization with the backward movement of the first slide member 107, the second slide member 108 moves forward in the direction of the arrow 108A.
When the first slide member 107 starts the backward movement in this way, the first swinging member 100 cantilevered on the first slide member 107 rotates in the direction of the arrow 100B about a fulcrum 100c because a cam groove 107a in the first slide member 107 guides a follower pin 100b. As a result, the tip pin 10a of the first swinging member 100 carries the disc D in the direction of the arrow 107A until the disc impinges on pins 111a, 111b of a disc positioning member 111.
At this time, the tip pin 103a of the second swinging member 103 rotates in the direction of the arrow 103A. Accordingly, the tip pin 103a of the second swinging member 103 supports the disc D in synchronization with the tip pin 100a of the first swinging member 100 and moves in the direction of the arrow 103A. After the disc D impinges on the pins 111a, 111b of the disc positioning member 111, the tip pin 103a rotates to a position slightly apart from the disc D.
The foregoing is associated with the operation mode of the loading mechanism when the disc D is carried in the device. When the disc D is carried out of the device, in contrast, the loading mechanism operates in the reverse operation mode to the foregoing. Namely, when the disc D is located in place inside the device as shown in FIG. 52, the drive means 106 is actuated in the direction of reverse rotation based on a carry-out instruction. In this case, the first slide member 107 starts to move forward in the direction of the arrow 107B and, in synchronization with this movement, the second slide member 108 linked to the slide link member 109 moves backward in the direction of the arrow 108A. As a result, the first swinging member 100 rotates in the direction of the arrow 100A and the second swinging member 103 in the direction of the arrow 103B. Accordingly, the tip pins 100a, 103a support the disc D and carry it out of the device.
The disc D carried inside the device is clamped on a clamp head 112 that can move upward/downward in place. The clamp head 112 is integrated with a turntable 113 fixed to a drive shaft of a spindle motor 114. The spindle motor 114 is disposed on a frame member (not shown). An elevator mechanism is used to move the frame member upward/downward (for example, Patent Document 1: JP 2002-117604A).
As described above, in the disc device of the slot-in type, the disc is inserted through the slot in the front bezel and housed in the device through the application of automatic loading. In this state, the disc can not be viewed from the outside. In particular, the slot in the front bezel has an aperture width designed minimum. In addition, if a shield member is provided to prevent dusts from entering, it is made quite impossible to view the disc.
In the disc device of the slot-in type thus configured, even if the disc housed inside the device is being driven, another disc may be erroneously inserted into the slot. In such the case, the outer rims of both the discs contact each other to lower the rotation speed of the driven disc, leaving a risk of critical damages imposed on reading/writing data from/in the disc.
To solve such the problem, the existing product of the present applicant includes a shutter configured to move upward/downward at the central portion of the slot in the front bezel. The shutter is used to prevent another disc from entering. FIG. 53 shows an arrangement for allowing the shutter to move upward/downward. The arrangement includes a slide member 201 having a vertical groove 201a formed at an end and capable of laterally sliding. The slide member 201 is disposed on a front flange 202c of a base panel 202 having a pair of slanting grooves 202a, 202b formed therethrough. The shutter 203 has a pin 203a provided at the lower end thereof, which is inserted into the vertical groove 201a and the slanting groove 202a at the same time, and the other pin 203b, which is inserted into the slanting groove 202b, to assemble the arrangement.
Therefore, as the slide member 201 slides in the direction of the arrow as shown in FIG. 53(B), the vertical groove 201a pulls the pin 203a on the shutter 203. As a result, the pin 203a ascends along the slanting groove 202a and the shutter 203 ascends to a position sufficient to block the central portion of the slot in the front bezel as shown in FIG. 53(C). Namely, the slanting groove 202a is configured to forcibly convert the lateral force of the slide member 201 into the longitudinal force.
As configured above, the width in the longitudinal direction of the vertical groove 201a and the slanting grooves 202a, 202b for moving the shutter 203 upward/downward corresponds to the stroke of the shutter 203 moving upward/downward. Accordingly, the width in the longitudinal direction can not be made smaller than the latter. Namely, the width in the longitudinal direction of the front flange 202c of the base panel 202 is determined from the vertical groove 201a and the slanting grooves 202a, 202b. Therefore, the width of this portion can not be reduced further and indicates the limit of thinning the disc device.
An ascent/descent of the pin 203a utilizes variations in mutual position of the vertical groove 201a and the slanting groove 202a. Therefore, a sliding contact resistance occurs between the pin 203a and each groove and requires a larger drive torque. This is not a suitable arrangement for seeking stable operation with no variation overtime. Further, when the shutter 203 reaches the highest state, the lower end thereof supports two pins 203a, 203b at the tip of a shutter cover 204. Accordingly, the shutter is cantilevered and the structural hardness can not be enhanced. Thus, the structure becomes unstable such that it easily tumbles when the disc D impinges thereon as shown in FIG. 54 and damages the rim of the disc D as a malfunction.
Even the shutter 203 thus configured can block the entry of a large diameter disc D1 generally referred to as a 12 cm disc and prevent it from contacting another large diameter disc D1 housed inside the device and driven as shown in FIG. 55. Incidentally, a small diameter disc D2 generally referred to as an 8 cm disc may be inserted erroneously. In such the case, part of the small diameter disc D2 enters between one aperture end of the slot in the front bezel and a side end of the shutter 203 and contacts the large diameter disc D1.
Specific numeric values may be applied to this case. For example, when the slot has a standard total aperture width W1 of 120.8 mm, and the shutter 203 has a total width W3 of 10.6 mm, one aperture end of the slot and the side end of the shutter 203 opposed thereto has a width W2 of 55.1 mm. Thus, the large diameter disc D1 contacts the small diameter disc D2. Therefore, it is required to make the total width W3 of the shutter 203 larger than 10.6 mm and the width W2 smaller than 55.1 mm. The above-described numeric values are minimum numeric values for fundamental design on the assumption that a clamp head locates on the central position of the slot. If the clamp head deviates from the central position of the slot either left or right, or if a front bezel with a larger depth is used and it changes the difference between the slot aperture and the clamp head, setting of numeric values corresponding to the state is required.
Such the malfunction is a problem that may arise even in a disc device configured to drive only the large diameter disc D1. The disc device configured to drive both the large diameter disc D1 and the small diameter disc D2 increases the probability of the erroneous insertion of the small diameter disc D2 because the user strongly recognizes that the device can also drive the small diameter disc D2.
A simple means for solving such the problem is to merely widen the shutter 203 though this means increasingly lowers the structural hardness. Even with such the provision, a mechanical problem on the upward/downward movement of the shutter 203, and a critical subject to reduce the width in the longitudinal direction of the front flange 202c of the base panel 202 to thin the entire disc device are left unsolved.